108 AMERICAN HYMENOPTERA. 



are perhaps the most widely distributed, the former ranging 

 from southern Canada to Central America, and the latter 

 apparently from Central Mexico to Peru. 



Variation. — Members of this genus show some variation 

 in color, especially in the amount of black. This is well 

 brought out in T. niorio and its subspecies transitionalis 

 where the head and legs are sometimes more or less flavous 

 or tinged with ferruginous. This variation is somewhat 

 similar to that seen in A. airiventris, but the limits are not 

 yet known, and T. snowi may prove to be a continuation of 

 this. The violet-blue reflection seen in T. cyaneus and T. 

 grandis may also prove to be simply variation, but breeding 

 experiments are needed to settle these questions. 



Economic importance. — The value of the members of this 

 genus as parasites can not be estimated, for most of them 

 are tropical and their hosts are unknown. So far as known, 

 however, they are parasitic upon Sphingidas. 



Life history and habits. — Little is known of the life history 

 or habits of the members of this genus, but that of T. morio 

 is probably typical, and this, so far as known, is given under 

 that species. 



Table of Species. 



1. Wings entirely black, with or without cyaneous reflection 2. 



Wings ttot entirely black, with or without cyaneous reflection ...13. 



2. Body entirely black, with or without cyaneous reflection 3. 



Body not entirely black, with or without cyaneous reflection 9. 



3. Antennae entirely black 4. 



Antennae not entirely black 6. 



4. Body and wings with a distinct cyaneous reflection 5. 



Body without a distinct cyaneous reflection niger Cress. 



5. Face and thorax with dense pubescence... iiigTO-caenileus Cam. 

 Face and thorax without dense pubescence cyaueiis Br. 



6. Antennae yellowish-white, with base and apex black. 



iiiorosus Sm. 

 Antennae not j'ellowish-white 7. 



7. Antennae black, flavous below niger Cress. 



Antennae flavous or orange flavous (reddish), base and apex 



sometimes black 8. 



8. Body and wings with distinct cyaneous reflection.. grrandis Cress. 

 Body and wings without distinct cyaneous reflection 21. 



9. Abdomen fulvous, slightly marked with black affiiiis Cress. 



Abdomen 7iot fulvous 10. 



